I had a wonderful sushi last night. However, I am very new to the Eastern (and specially sushi) kitchen. I know there are uncountable recipes online for making all kinds of sushi. I would like to know if someone knows a good recipe for making sushi (preferable with salmon) rolled in some kind of black leaf. I am sorry, but I don't know the right word for it. The sushi I mean is showed in the picture below.
I just don't know how to start this, and where I get all the ingredients. Can I buy them in the grocery store, or do I need to go to a special shop (I live in Belgium, so we don't have the same stores as in America)

Sushi rice is a short-grain, glutinous rice, and I believe it is mixed with vinegar to make it stickier. The black leaf-like substance is nori, dried seaweed. Both the rice and the nori should be available at Asian markets. The key will be the freshest fish you can find.

From "Cooking Ingredients" by Christine Ingram: "In the West, several varieties of suitable Japanese sushi rice are available. Although not actually a glutinous rice, it has sticky properties, a characteristic common to all Japanese rices."
From "Japanese Country Cookbook" by Russ Rudzinski (my first Japanese cookibook, copyright 1969): the rice is cooked, cooled, then soaked in a vinegar and sugar mixture, 1:1, brought to a boil. Use 1 - 2 Tablespoons of the liquid per cup of cooked rice. The simplest sushi is a mound of rice, shaped (should stick together), garnished (such as the fish). The rolls are called nori maki, and filling ingredients are cut in strips as long as the roll.
They are typically served with soy sauce, wasabi (called Japanese horseradish, but it's a different plant, just has the effect of horseradish), and slices of ginger that have been pickled.
If you can find a restaurant that has a sushi bar, you can sit and watch the sushi chef (who typically has had extensive training) making the sushi -- how he cuts the fish, how he handles the rice, how he fills and rolls the nori... and look online for videos. I think you need to see them made, spend time and ingredients practicing -- and eating and enjoying so you can try many variants. I hope you will be able to find what you need, learn the techniques, and adapt as necessary to what is available to you locally.